P1494: INDICATIONS OF HEMATOPOIETIC STEM CELL TRANSPLANT ACCORDING TO DIFFERENT SETS OF INDICATIONS AND ANALYSIS OF COMORBIDITY INDEX SCORES IN BRAZILIAN PATIENTS WITH SICKLE CELL DISEASE
Authors: G. Santos, K. Tozatto-Maio, L. Alves, G. Fonseca, G. Melo, L. Suganuma-Otsuka, F. Nogueira, A. Cardoso, V. Rocha, S. Gualandro
Journal: HemaSphere (2022)

Background: Hematopoietic stem cell transplantation (HSCT) is the only curative therapy currently available for sickle cell disease (SCD). However, HSCT indications might vary across countries, and who should not be transplanted is still a matter of debate since HSCT mortality scores lack validation in SCD settings. Aims: To identify how many patients currently followed at the SCD outpatient service of the Hospital das Clínicas de São Paulo meet at least one indication for HSCT, either according to the Brazilian Ministry of Health (BMH) or to an international expert panel (Angelucci et al, 2014); to characterize the distribution of the hematopoietic cell transplantation comorbidity index (HCT-CI) and Charlson comorbidity index (CCI) scores in this cohort, comparing the scores between transplantable and non-transplantable population to correlate them with the severity of the disease. Methods: Single-center, retrospective study with 219 patients with SCD. Using the set of HSCT indications either from the BMH or Angelucci, we determined the frequency of patients with >1 indication. The concordance between the two sets of indications was assessed using Cohen’s kappa coefficient. HCT CI and CCI were used to assess risk of HSCT-related severity; median scores in transplantable and non transplantable populations were compared using Mann-Whitney. Results: We included 219 patients, of which 143 were SS genotype, 47 SC and 29 Sβ;138 were female. The median age of the cohort was 38(range,20-74) years. 33 patients had ischemic stroke, 2 had hemorrhagic stroke and 10 had Moya-moya. 125 patients had acute chest syndrome and 210 had vaso-occlusive crisis (VOC), of whom 74 had >3 VOC in the last 12 months. 11 patients had pulmonary arterial hypertension, 73 had avascular necrosis, 35 priapism, 65 proliferative retinopathy and 184 proteinuria. 103 patients were under hydroxyurea and 48 had previously used. 186 received blood transfusion, 47 being under exchange transfusion program; 72 were alloimmunized. 168 patients had at least one HSCT indication, 108 by the BMH and 166 by Angelucci; 60 met an indication only by Angelucci and 2 only by the BMH. The overall agreement rate between the 2 sets was 0.71, with a Cohen’s kappa coefficient of 0.44. When only SS and SB0 patients are considered, the Cohen’s kappa coefficient remains moderate (0.50). The main indication by both sets was alloimmunization, followed by CNS event (BMH) and recurrent VOC (Angelucci). Among age groups, the number of patients with >1 TCTH indications was:18-30 years:46; 31-40 years:50;41-50 years:31;51-60 years:24;+60 years:17. The median HCT-CI score in the transplantable population was 2(range,0-12) and in the non-transplantable population was 1(range,0-5)(p=0.004); median CCI was respectively 1(range,1-9) and 0(range,0-3) (p<0.001). Summary/Conclusion: HSCT indications according to the BMH are stricter than those proposed by Angelucci et cols, which explains the moderate agreement on Cohen’s kappa coefficient.The rate of indications is higher than in previously reported similar cohorts, mainly due to the higher rate of alloimmunization and older median age of our cohort, as HSCT indications increase over time in SCD. Median HCT-CI and CCI were significantly higher in the population with >1 HSCT indication, reflecting the higher severity of these patients.Although this might mean that such severity scores can be used to predict severity in SCD patients, further validation in prospective HSCT cohorts is warranted.